I am little confused in tie-line concept. according to me a tie line is a connection between two areas through which power sharing can happen. Some questions:

1.What governs the power transfer through a tie line.

2.Can it be modelled as a low impedance path between the two networks.

3.Can the tie line be there between two buses of different voltages.

 

Responding to Muttoo’s 06-Jan (13:11)... your query can't be answered with one word, Not even a single paragraph! But here are some of my thoughts:

1) Definition.
The IEEE Std 100, definition covering electric power systems is, "A transmission line connecting two power systems!"

2) What Governs Its Operation?
A power pool! The power pool is a conglomeration of individual power producers operating under contractual agreement to exchange the "flow" of power through tie-lines, as well abide by procedures that should maintain system frequency! It’s an operation that has aged many a system operator. Some put it right up there with air-traffic controllers!

3) How Is It Modeled?
With great trepidation, many computers, and some exacerbation! Modeling starts with an under-standing of the control algorithm associated with a two-generator system, then three-generators, then four, and so on. An analogy I use likens it to a waiter tryng to deliver wine (power) to patron's table in a flat dish, while simultaneousl trying to deliver water (reactive volt-amperes) to another table... in the same dish!

4) Low Impedance Path?
The impedance plays a huge role! But it is no less important than machine inertia, voltage regulator speed, and many other concerns!

5) Termination Voltages Differences.
Yes, both in magnitude and phase-displacement.

Muttoo, I don't know your level of expertise in this subject, but there are some who have made life-time careers understanding the proper care and handling of power-pool operation!

Regards, Phil Corso (cepsicon @aol.com)

 

I think what you are asking about is a telephone tie line.

It is simply a dry pair for the connection of remote points.

An example is a remote office that you want to be connected to your PBX. You rent a pair from your building to the remote office. It is essentially the same thing as running your own line, but without the expense. You usually pay an installation fee and a monthly or yearly line rental.

 

No, no, I meant electrical tie line only, which is an interconnection between two areas.

But still thanks for this information also